Starting system



Nov. 23, 1965 L. c. JENNINGS STARTING SYSTEM Filed July 23, 1964 EOkOE ATTORNEYS United States Patent 3,218,797 STARTING SYSTEM Lyston C. Jennings, Watertown, N.Y., assignor to The New York Air Brake Company, a corporation of New Jerse y Filed July 23, 1964, Ser. No. 384,646

2 Claims. (Cl. 60-19) This invention relates to hydraulic starting systems for engines, and particularly for engines of the turbine type.

The object of the invention is to provide a lightweight, simple, relatively inexpensive and automatic hydraulic starting system.

The preferred embodiment of the invention is described herein with reference to the accompanying drawing whose single figure is a schematic diagram of the system.

As shown in the drawing, the starting system includes a fixed displacement starter motor 1, a supply pump 2, and a supply conduit 3 which connects the discharge port 2:: of the pump with the inlet port 1a of the motor. Motor 1 discharges to a hydraulic reservoir 4 which serves as a source of fluid for pump 2. Pump 2 is driven by a prime mover (not shown) and motor 1 is connected with the engine 5 through a one-way, overrunning clutch 6. The supply pump 2 may be either a variable delivery, discharge pressure compensated pump or a fixed delivery pump provided with a relief valve.

Interposed in supply conduit 3 is a start valve 7 which is biased closed and which has an actuating solenoid 7a that is connected in an electrical circuit including battery 8 and switches 9 and 11. Switch 9 is provided with a holding coil 9a so that once it is closed by the operator it remains closed until switch 11 opens. Switch 11 is biased closed by a spring 12 and is opened by a diaphragm actuating motor 13. The opposed working spaces 13a and 13b of motor 13 are connected with the entrance and throat, respectively, of a venturi 14 located in conduit 3. It will be understood that the parts 11, 12, 13 and 14 constitute a flow sensitive switch that opens whenever the rate of flow through supply conduit 3 exceeds a predetermined value. In accordance with the invention, this value is the flow demand of motor 1 at starter cut-out speed, i.e., a speed higher than ignition speed at which the engine is capable of independent operation.

Assuming that pump 2 is running, the starting cycle is initiated by depressing switch 9 to thereby complete the electrical circuit and cause solenoid 7a to open start valve 7. Fluid discharged by pump 2 may now flow to 3,218,797 Patented Nov. 23, 1965 and through motor 1 causing it to develop torque and accelerate engine 5. As the speed of the engine increases, so too does the flow demand of motor 1, and consequently the rate of flow through supply conduit 3. Thus, the switch-opening force developed by the pressure differential between spaces 13a and 13b of actuating motor 13 commences to increase. However, until the engine reaches cut-out speed, this force is not large enough to overcome the opposing bias or spring 12 and switch 11 remains closed. When the engine 5 is accelerated to this speed, motor 13 overpowers spring 12 and opens switch 11. As a result, starting valve 7 closes and interrupts the flow of fluid to motor 1. Therefore, the starter motor comes to rest. Since opening of switch 11 de-energizes holding coil 9a, and thus allows switch 9 to open, the system is automatically reset for the next starting cycle. As stated previously, the drawing and description relate only to the preferred embodiment of the invention. Since changes can be made in the structure of this embodiment without departing from the inventive concept, the following claims should provide the sole measure of the scope of the invention.

What I claim is: 1. A hydraulic starting system comprising (a) a source of hydraulic fluid under pressure; (b) a fixed displacement hydraulic motor; (0) a supply conduit for leading fluid from the source to the motor; and (d) means responsive to the rate of flow through the supply conduit for terminating the supply of fluid to the motor when the rate of flow exceeds a predetermined value. 2. A hydraulic starting system for accelerating an engine to starter cut-out speed comprising a pp y p p; (b) a fixed displacement starter motor; (0) a supply conduit for leading fluid from the source to the motor; (d) a start valve controlling flow through the supply conduit; (e) means for opening the start valve; and (f) means responsive to the rate of flow through the supply conduit for closing the start valve when the rate of flow exceeds a predetermined value indicative of starter cut-out speed.

No references cited.

JULIUS E. WEST, Primary Examiner. 

1. A HYDRAULIC STARTING SYSTEM COMPRISING (A) A SOURCE OF HYDRAULIC FLUID UNDER PRESSURE; (B) A FIXED DISPLACMENT HYDRAULIC MOTOR; (C) A SUPPLY CONDUIT FOR LEADING FLUID FROM THE SOURCE TO THE MOTOR; AND (D) MEANS RESPONSIVE TO THE RATE OF FLOW THROUGH THE SUPPLY CONDUIT FOR TERMINATING THE SUPPLY OF FLUID TO THE MOTOR WHEN THE RATE OF FLOW EXCEDS A PREDETERMINED VALUE. 